Seat Articulating Device

ABSTRACT

The invention concerns a seat articulating device comprising a seat and a back capable of pivoting relative to the back seat about a pivot pin (A 1 ) into a plurality of positions, in particular a nominal position wherein the back is substantially vertical and a shelf position wherein the back is folded down on the seat, said device comprising: a flange ( 3 ) designed to support the back pivoting relative to the pivot pin (A 1 ) including arc-shaped teeth having a radius R centered on the pivot pin (A 1 ); a concave toothed segment ( 12 ) capable of being linked to the seat, oscillating relative to a pivot pin (A 2 ) between a locking position wherein it co-operates with the teeth of the flange ( 3 ) and an unlocking position wherein it is spaced apart from the flange teeth and allows the flange ( 3 ) to rotate. The invention is characterized in that it comprises: a projecting part ( 6 ) of the flange surface ( 3 ) forming an arc-shaped ramp ( 7 ) centered on the pivot pin (A 1 ) having a radius r smaller than the radius R of the teeth wherein is provided a groove ( 8 ), and an oscillating lever ( 23 ) located in the same plane as the projecting part ( 6 ) of the flange ( 3 ), coaxial and superimposed to the toothed segment ( 12 ) including a tooth ( 27 ) capable of sliding on the ramp ( 7 ), when the back pivots between the nominal position and the shelf position and capable of being locked in the groove ( 8 ) of the projecting part when the seat is in the shelf position.

The present invention relates to a motor vehicle seat that has a seat cushion and a backrest, it being possible for the backrest to occupy several positions of inclination with respect to the seat cushion.

In the specifications for numerous vehicles, particularly station wagons or people carriers, the cabin is required to demonstrate modularity. This modularity is essentially provided by the seats which need to be able to adopt different configurations in order, as need be, to:

-   -   be deployed in order to accommodate passengers,     -   be folded in order to adopt a compact configuration,     -   be removed from the vehicle.

Furthermore, the seats need to meet certain safety standards and need therefore to be able to absorb a considerable deceleration as the result of an accident, while at the same time restraining the passenger seated in them. In the case of a seat that carries its own safety belt, it is the actual structure of the seat that has to be able to react the forces caused by sudden deceleration.

Conventionally, a seat has a seat cushion on which a backrest is articulated such that it can rotate. The backrest has a nominal position in which the backrest is inclined slightly backward in order to accommodate a passenger ergonomically and comfortably. The inclination of this backrest can be adjusted by a few degrees forward or backward of this nominal position.

For that, the seat cushion is equipped with a toothed sector and the backrest that can rotate relative to the seat cushion is also equipped with a toothed sector. These two sectors mesh with one another and, depending on the position of one toothed sector with respect to the other, the backrest will have a particular inclination chosen by its occupant.

It can therefore be seen that the forces, particularly in the event of an accident, experienced by the backrest are absorbed by the seat cushion via the toothed sectors belonging to the backrest and to the seat cushion.

These forces are all the higher if the backrest carries a safety belt which then restrains the passenger.

It is therefore important that, in the event of an accident, the mechanical connection between the backrest and the seat cushion be strong enough not to yield.

One arrangement which allows the seat to absorb forces with a high longitudinal component consists in giving the toothed sector with which the backrest is provided a large radius of curvature. This therefore means that the toothed sector will occupy a great deal of space.

Furthermore, in order to provide the required modularity, a seat needs to be able to be used in what is known as a “table” configuration, that is to say in a configuration in which the backrest is folded down onto the seat cushion and the rear face of the backrest lies more or less horizontal and can be used as a surface to accept items or as an armrest.

In this configuration, the backrest has of course to be locked relative to the seat cushion. This locking function is normally the job of the toothed sector.

Now, in the case of a seat that carries its own safety belt, the distance separating the axle of rotation of the backrest from the toothset of the toothed sector needs to be great for the reasons explained above.

The toothed sector which immobilizes the backrest, both in its nominal position and in its table position, leads to a mechanism that is very bulky.

It is one object of the invention therefore to propose a motor vehicle seat that has an articulation device which, while at the same time as being compact, is able to withstand significant forces, particularly in the case of a seat that carries its own safety belts and locks the backrest in its nominal position and in its table position.

The subject of the invention is, essentially, a device for articulating a seat comprising a seat cushion and a backrest that can pivot with respect to the seat cushion about an articulation axle into multiple positions, particularly a nominal position in which the backrest is more or less vertical and a table position in which the backrest is folded down onto the seat cushion, this device comprising:

-   -   a side plate intended to support the pivoting backrest with         respect to the articulation axle and having a toothset in the         form of an arc of a circle of radius R, centered on the         articulation axle,     -   a concave toothed sector that can be connected to the seat         cushion, pivoting with respect to an articulation axle between a         locking position in which it collaborates with the toothset of         the side plate and an unlocking position in which it is distant         from the toothset of the side plate and allows the side plate to         rotate,         characterized in that it comprises:     -   a projecting part projecting from the surface of the side plate         and forming a ramp in the form of an arc of a circle centered on         the axle of rotation and of radius r smaller than the radius R         of the toothset and exhibiting a cut-out, and     -   a pivoting lever lying in the same plane as the projecting part         of the side plate, coaxial and superposed with the toothed         sector and having a tooth able to slide along the ramp as the         backrest is pivoted between the nominal position and the table         position and able to click into the cut-out of the projecting         part when the seat is in the table position.

The idea underlying the invention is that of creating a two-stage device, namely one which has a first stage consisting of a toothed side plate of large radius for transmitting potentially great forces when the seat is in the nominal position, and a second stage consisting of a small-radius projecting part for locking the seat in the table position.

According to one advantageous embodiment, the projecting part has a stop surface which faces the tooth when the seat is in the nominal position.

This arrangement allows the behavior of the seat to be improved in the event of sudden decelerations. Specifically, if the side plate pivots as the result of an accident, that is to say the toothset of the side plate slips with respect to the toothed sector, the stop on the projecting surface of the side plate comes to bear against the tooth of the lever and affords additional support to absorb the energy of the deceleration.

To ensure that the lever and the toothed sector behave as one, the toothed sector has a boss which engages in a slot made in the lever.

According to a preferred embodiment, the toothed sector has a bearing surface adjacent to a cut-out bounded by a snout, the device additionally comprising a primary finger pivoting with respect to an axle between a locking position in which it is in contact with the bearing surface, keeping the toothed sector in mesh with the toothset of the side plate, and an unlocking position in which the primary finger faces the cut-out and comes to bear against the snout in order to cause the toothed sector to pivot.

In addition, a spring is positioned on the axle about which the primary finger pivots, the action of this spring tending to cause the primary finger to pivot against the bearing surface of the cogged sector.

As a preference, the lever has a bearing surface adjacent to a cut-out, the device additionally comprising a secondary finger engaged on the same axle of pivoting A3 as the primary finger, pivoting between a position in which it is in contact with the bearing surface so as to keep the lever in an angular position such that the tooth is engaged in the cut-out of the projecting part of the side plate and an angular position in which the tooth of the lever slides along the ramp as the backrest pivots about the axle.

Advantageously, the primary finger and the secondary finger are oriented with respect to one another in such a way that, in the nominal position, the primary finger is in contact with the bearing surface of the toothed sector and the secondary finger is in contact with the bearing surface of the lever and in such a way that, in an intermediate position between the table position and the nominal position, the primary finger bears against the snout of the toothed sector and the secondary finger is engaged in the cut-out of the lever.

According to one possible embodiment, all the elements of the device are enclosed in a casing that is closed by a cover.

To avoid noise, it comprises a hairpin spring which bears against the toothed sector and against the lever.

The angular travel of the backrest is limited because the casing is equipped with a stop against which the side plate comes to bear on the backrest in the backward nominal position against which the side plate bottoms out, in the table position.

For a good understanding thereof, the invention is described with reference to the attached drawing which, by way of nonlimiting example, depicts one embodiment of an articulation mechanism according to this invention.

FIG. 1 is a perspective view of the mechanism supported by a casing,

FIG. 2 is a front view of the mechanism in the forward nominal position, depicting the first stage of the mechanism but omitting the second,

FIG. 3 is a view similar to FIG. 2, with the mechanism in the backward nominal position,

FIG. 4 is a view of the mechanism in a configuration in which the backrest can be rotated,

FIG. 5 depicts a front view of the complete mechanism,

FIG. 6 depicts the complete mechanism in a configuration in which the backrest is allowed to rotate,

FIG. 7 depicts the mechanism in the process of rotating,

FIGS. 8 and 9 show the mechanism in a configuration in which the seat is in the table position.

The seat articulating mechanism according to the invention as shown depicted in FIG. 1 is a two-stage mechanism.

The first stage of this mechanism is more clearly depicted in FIGS. 2 to 4 because in those figures the second stage has not been depicted.

With more particular reference to these figures, it is evident that the device is contained in a casing 2. This device comprises a side plate 3 articulated for rotation with respect to an axle A1. Although this is not shown in the drawing, the side plate 3 is connected to the backrest and it is therefore the side plate 3 which provides the connection between the backrest and the seat cushion. The casing 2 is, in fact, secured to the seat cushion of the seat.

The side plate 3 has a toothset 4 in the form of an arc of a circle, the toothset 4 being centered on the articulation axle A1. The toothset 4 lies on an arc of a circle of radius R with respect to the axle A1.

The side plate 3 also has a projecting part 6 which, in the example depicted, is obtained by partial cutting. This projecting part 6 could, in another embodiment, be added-on and attached to the side plate 3 by welding.

This projecting part 6 has a ramp 7 in the form of an arc of a circle of radius r centered on the articulation axle A1. The projecting part has two other important structural features: a cut-out 8 and a more or less radial bearing surface 9.

Rotation of the side plate 3 is halted by a stop 10 supported by the casing 2.

The side plate 3 is locked in position by a toothed sector 12 able to move with respect to an articulation axle A2, this articulation axle A2 being supported by the casing 2. This toothed sector 12 has a concave toothset 13 which, when in mesh with the toothset 4 of the side plate 3 prevents the latter from rotating.

The toothed sector 12 is kept in contact with the toothset of the side plate 3 by a rotary primary finger 15 which comes into contact with a bearing surface 16 formed in the toothed sector 12. The primary finger 15 is engaged on an articulation axle A3 supported by the casing 2. A spiral spring 18 urges the primary finger 15 into a position in which it bears against the bearing surface 16 of the toothed sector 12.

Although this is not depicted in the drawing, the primary finger 15 is connected by an operating linkage to a member that can be manipulated by an operator to rotate the primary finger in the clockwise direction with reference to the drawings.

When the primary finger 15 rotates in the clockwise direction, it then finds itself facing a cut-out 20 adjacent to the bearing surface 16 of the toothed sector 12.

At the end of rotation, the primary finger 15 presses against a snout 22 bordering the cut-out 20 of the toothed sector 12. The primary finger 15, by bearing against the snout 22 of the toothed sector 12, causes the latter to pivot with respect to its rotation axle A2. FIG. 4 illustrates this configuration of the device. It can therefore be seen that the toothset 4 of the side plate 3 is disengaged from the toothset 13 of the toothed sector 12.

The side plate 3, which supports the backrest together with a second side plate 3 symmetrical with the first relative to the seat cushion, allows the inclination of the backrest to be adjusted about its nominal position (FIG. 3 depicting the side plate 3 and therefore the backrest in the backward nominal position) or allows it to be pivoted forward.

One point that is important to note regarding this first stage of the device is that the radius of the toothset 4 is particularly great and allows this device to be fitted to a seat the backrest of which carries a built-in safety belt.

FIGS. 5 to 9 show the device in its entirety and reveal the second stage of the device.

As shown by FIG. 5, the device is further equipped with a lever 23 which is engaged on the articulation axle A2 on which the toothed sector 12 is already articulated.

The toothed sector 12 is secured to the lever 23 by a boss 24 protruding from the surface of the toothed sector 12 and engaging in a slot 25 made in the lever 23.

It can therefore be seen that when the toothed sector 12 is rotated, it takes the lever 23 with it.

It will be noted that the lever 23 at its end has a tooth 27 and also has a bearing surface 28 adjacent to a cut-out 29.

A hairpin spring 30 bears both against the toothed sector 12 and against the lever 23 in order to avoid noise due to shaking transmitted to the seat and which could cause the elements of the device to knock together.

The last important element in the second stage is the presence of a secondary finger 32 engaged on the articulation axle A3 of the primary finger 15.

FIG. 5 depicts the device in its nominal position. In this position, the secondary finger 32 bears against the bearing surface of the lever and the tooth 27 faces the bearing surface 9 of the projecting part 6 of the side plate 3.

One point that must be noted is that, although the projecting part 6 of the side plate 3 is in the same plane as the lever 23 and as the secondary finger 32, these three elements functionally form part of the second stage of the device even though, structurally, the projecting part 6 is incorporated into the side plate 3.

It may be pointed out that this device, although it is a two-stage device, is of relatively modest thickness as can be seen in FIG. 1.

The way the device works is as follows: when the mechanism is in its configuration depicted in FIG. 5, the side plate 3 is locked because its toothset 4 is engaged in the toothed sector 12 which is itself locked by the primary finger 15.

Were a user to wish to alter the inclination of the backrest with respect to the seat cushion, he would act on an operating member to rotate the primary finger 15.

FIG. 6 illustrates this configuration of the device in which the primary finger 15 is given a rotational movement to cause it to come to bear against the snout 22 of the toothed sector 12 and cause it to pivot in such a way as to disengage the toothed sector 12 from the toothset 4 of the side plate 3.

In this position, the side plate 3 is free to rotate. The user can then choose either to adjust the inclination of the backrest about its nominal position, or to pivot it toward the seat cushion in order to place it in a so-called table position.

FIG. 7 shows the movement of the backrest from its nominal position into its table position. It may be seen that, during this movement, the secondary finger 32 is engaged in the cut-out 29 made in the lever, and does not therefore oppose the pivoting of the assembly comprising the toothed sector 12 and the lever 23. At the same time, the tooth 27 of the lever slides along the ramp 7 of the projecting part 6.

One point that should be emphasized is that the user can release his action on the articulation axle A3 because the device is guided in its rotation by the tooth of the lever sliding along the arc-shaped ramp.

At the end of its travel, as can be seen in FIG. 9, the tooth 27 of the lever 23 clicks into the cut-out 8 made in the projecting part 6 of the side plate 3. The secondary finger 32 is then returned by the spiral spring 18 and comes to bear against the bearing surface 28 of the lever 27, thus locking the side plate 3 in this position.

FIGS. 8 and 9 show the entirely noteworthy aspect of this mechanism which is the fact that the second stage locks the backrest but to do so requires very much less space than is required by the toothset of the side plate of the first stage for locking the backrest in position.

The invention therefore provides a device which, while at the same time requiring a small amount of space, allows a seat backrest to be locked both in the nominal position and in the table position.

Of course, the invention is not restricted to the form of embodiment described hereinabove by way of non-limiting example but on the contrary encompasses all embodiments thereof. 

1. A device for articulating a seat comprising a seat cushion and a backrest that can pivot with respect to the seat cushion about first articulation axle into multiple positions, particularly a nominal position in which the backrest is more or less vertical and a table position in which the backrest is folded down onto the seat cushion, this device comprising: a side plate intended to support the pivoting backrest with respect to the first articulation axle and having a toothset in the form of an arc of a circle centered on the articulation axle, a concave toothed sector that can be connected to the seat cushion, pivoting with respect to second articulation axle between a locking position in which it collaborates with the toothset of the side plate and an unlocking position in which it is distant from the toothset of the side plate and allows the side plate to rotate, a projecting part projecting from a surface of the side plate (3) and forming a ramp in the form of an arc of a circle centered on the first axle of rotation and of radius smaller than a radius of the toothset and exhibiting a cut-out, and a pivoting lever lying in the same plane as the projecting part of the side plate, coaxial and superposed with the toothed sector and having a tooth able to slide along the ramp as the backrest is pivoted between the nominal position and the table position and able to click into the cut-outs of the projecting part when the seat is in the table position.
 2. The device as claimed in claim 1, wherein the projecting part has a stop surface which faces the tooth when the seat is in the nominal position.
 3. The device as claimed in claim 1, wherein the toothed sector has a boss which engages in a slot made in the lever.
 4. The device as claimed in claim 1, wherein the toothed sector has a bearing surface adjacent to a cut-out bounded by a snouts, the device additionally comprising a primary finger pivoting with respect to an axle between a locking position in which it is in contact with the bearing surface, keeping the toothed sector in mesh with the toothset of the side plate, and an unlocking position in which the primary finger faces the cut-out and comes to bear against the snout in order to cause the toothed sector to pivot.
 5. The device as claimed in claim 4, wherein a spring is positioned on the axle about which the primary finger pivots, the action of this spring tending to cause the primary finger to pivot against the bearing surface of the toothed sector.
 6. The device as claimed in one of claim 4, wherein the lever has a bearing surface adjacent to a cut-out, the device additionally comprising a secondary finger engaged on the same axle of pivoting as the primary finger, pivoting between a position in which it is in contact with the bearing surface so as to keep the lever in an angular position such that the tooth is engaged in the cut-out of the projecting part of the side plate and an angular position in which the tooth of the lever slides along the ramp as the backrest pivots about the first axle.
 7. The device as claimed in claim 6, wherein the primary finger and the secondary finger are oriented with respect to one another in such a way that, in the nominal position, the primary finger is in contact with the bearing surface of the toothed sector and the secondary finger is in contact with the bearing surface of the lever and in such a way that, in an intermediate position between the table position and the nominal position, the primary finger bears against the snout of the toothed sector and the secondary finger is engaged in the cut-out of the lever.
 8. The device as claimed in claim 1, wherein elements of the device are enclosed in a casing that is closed by a cover.
 9. The device as claimed in claim 1, further comprising a hairpin spring which bears against the toothed sector and against the lever.
 10. The device as claimed in claim 8, wherein the casing is equipped with a stop against which the side plate comes to bear on the backrest in the backward nominal position against which the side plate bottoms out, in the table position. 